Variable-pitch propeller



0. F. PERS SON. VARIABLE PITCH PROPELLER.

APPLICATION FILED JAN. 24, 1920.

Pat tented Fe'b 14, 1922.

Inventor fklisflttorngg OttOF. Perss'or), by fl f UNITED STATES PATENT OFFICE.

OTTO 1. PERSSON, OF ERIE, PENNSYLVANIA.

VARIABLE-PITCH rnorELLEn.

To all whom it may concern:

-Be it known that I, O'r'ro F. PERSSON, a citizen of the United States, residing at Erie, county of Erie, State of Pennsylvania, have invented certain new and useful Improvements in Variable-Pitch Propellers, of which the following is a specification.

The present invention relates to variable pitch propellers and especially to those intended for use on air crafts, and has for its object to im rove their construction to the end that the lades may, by the expenditure of a reasonable amount of power, be turned to change their pitch while the propeller is rotating at high speed and performing work. A further object of the invention is to provide improved means whereby the reaction of the blades is prevented from being transmitted to the adjusting mechanism.

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and claims appended thereto.

In the drawing which illustrates one of the embodiments of my invention, Fig. 1 is a view largely in section through a propeller hub and its blades; Fig.- 2 is a partial end view of a four bladedpropeller showing certain of the actuating parts in section. Fig, 3 is a view in elevation of one of the metallic ferrules in which each blade is seated; Fig. 4 is a plan view of the same; Fig. 5 is a View partly in elevation and partly in section of the sleeve which turns the bladeson their axes, and Fig. 6 is a plan view thereof.

7 indicates one end of a well-known type of internal combustion engine and 8 the tapered crank shaft thereof. Keyed on the shaft'and held against endwise movement by the sleeve and nut 9 is the hub 10 of the propeller. Near its outer end the hub has a flange 11 to which is secured the casing 12, the latter being adapted the receive the'inner ends of the blades. In other words, the easing has sockets for receiving the blades of which there may be two .or more, four being illustrated. The casing is made in two principal parts and preferably of pressed steel, therev being a. flan e 13 on each part adjacent the plane of division through which a number of bolts 14 extend to securely unite them. A casing constructed in this manner is extremely strong and simple to manufacture. It is divided in the manner indicated so that the blades can readily be assembled in place or removed. The casing can be de-- Specification of Letters Patent. Patented Feb, 14, 1922, Application filed January 24, 1920. Serial No. 353,703.

signed to receive any reasonable number of blades 15, four being shown in the drawing. The mounting for each blade is similar so a description of one will suflice. On the inner end of each blade is a steel ferrule 16, the latter having a well rounded surface 17 at its inner end which terminates in a flange 18.

of a ball-bearing which bearing receives the heavy strain on-the blade-due to centrifugal force. By preference this ball or thrust bearing is closed to the shaft where the radius of the ferrule is somewhat larger in diameter than the intermediate part and is ground true to form a bearing surface for the rollers 21, the latter bein seated in an annular shouldered recess in t e casing and extending parallel with the axis ofthe blade. The purpose of these rollers is to take the side thrust of the blade when in service. It will be noted that the shape of these ball and roller containing parts of the casing is such as to form stiffening ribs thereby greatly strengthening the casing. This is chiefly due to the fact that a portion of the metal of each rib, as 22 for example, extends perpenp This rounded surface forms part of therace dicular to the cylindrical part of the casing.

It will be noted that the diameter of the to prevent the blade from pulling out. This is done by beveling ortapering the inner wall as at 23. Additional anchoring means are afforded by the saw tooth projections, ribs or ridges 24, which may be annular or only partially so. In assembling the steel ferrule is expanded by heat, care being exert is also to be noted as I ' end is then heated to shrink it and the two are forced together. After the blade is well seated in the ferrule an expanding bolt 25 having a coarse thread of the wood screw type is screwed into place which causes the inner end of the blade to enlarge and fill thesocket. This screw or bolt is prevented from backing out b the ar which is secured to the ferrule. s ad itional means for securing the blade wedges 26 may be driven into the end of the blade.

The actuating means for turning the blades will now be described. The hub which supportsthe casing has a conical bore and is keyed to the main shaft 8 of the engine. The periphery of the hub is cylindrical and has a number of axially extending grooves 30 which are parallel to'each other but angularly displaced. Surrounding the hub is a sleevefi31 which has a shoulder 32, Fig. 5, upon which is seated one member of the double acting thrust bearing 33. The sleeve is also screw threaded at 34 to receive the nut 35 the latter engaging a thrust disk 36. forming a part of the thrust bearing. The nut is he din place by any suitable form of locking means. Between the rows of balls is a thrust ring 37 which is moved to and fro by the lever 38 mounted at one'end on a swinging support 39 and an actuating rod and link 40. This rod may be moved by any suitable means.

The interior of the sleeve is provided with a plurality of broad, straight splines 41 which fit into the grooves 30 in the hub and permit it to be moved back and forth by the actuating rod without, however, changing its angular position with respect to the crank shaft and hub. On .the periphery of the sleeve is a plurality of broad spiral splines 42 as best shown in Figs. 5 and 6, there being eight in the present illustration. By preference both the inside straight splines and the outside spiral splines are made integral with the sleeve since byso doing their exact positioning-can be assured and they can be very accurately machined with a minimumamount of fitting. This arrangement also has the advantage of providing large wearing surfaces and avoiding the use-of loose parts. Surrounding-the sleeve-and located within thecasing is a tubular member 43 which is supported at its ends by suitable bearing surfaces formed on the actuating sleeve 31 and parts of the hub. Surrounding the member atits inner end, the one adjacent the engine, is a flanged ring 44 which serves to reinforce the casing. The inside or bore of the member is providedv with as many spiral slots as there are external splines on the sleeve 31, the arrangement being well,

illustrated in Fig. 2. Formed as a separate or integral part of the annular member is a beveled gear 45 which in turn meshes with ter in one direction. or the other depending upon the direction of movement of the sleeve. Axial movement of the sleeve is thus trans formed into circular movement ofthe member and with it the bevel gear 45, which in turn moves the blades about their axes to change their pitch. The angles of the spiral splines 42 and co-operating grooves are so chosen that while the sleeve can turn the blades the blades cannot by their reaction when in action move the sleeve, This is important since otherwise it would be very difficult to change the pitch of blades when in action and rotating at high speed.

The construction has the advantage of simplicity and great mechanical strength. Such parts as there are are comparatively few in number and do not require special straight line and angular makes the actuating mechanism such as 40 and associated parts very simple.

' -In accordance with the provisions of the patent statutes, I'have described the principle of operation ofmy inveritiom'together with the apparatus which I now consider to represent the best embodiment thereoffbut I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and-desire to secure by Letters Patent of the United States, is: 1. In a propeller, the combination of a hub adapted to be secured to. the driving shaft, a casing secured to the hub, blades carried by the casing, a tubular member which surrounds the hub, a sleeve arranged between the hub and member and in telescopic relation thereto, straight and spiral splines, certain of which are between the hub and sleeve and the others between the sleeve and tubular, member, and means for movingthe sleeve along the hub'to .8

angular movements of the blades on their axes.

2. In a propeller, the combination of a hub, a casing carried thereby, blades mounted in the casing and adapted to be moved about their axes to change their pitch, a tubular member, gearing between the member and the blades, a sleeve which has a straight line motion and is located between the hub and member forturning the latter, splines between the hub and 7 sleeve, other splines between the sleeve and member, and means for moving the sleeve on the hub to cause angular movements of the blades.

3. In a propeller, the combination of a hub, a casing carried thereby, blades mounted in the casin ,'a thrust and guide bearing for each bla e carried by the easing, a gear attached ,to each blade for turning it about its axis, a tubular member which carries a gear that meshes with all of the gears attached to the blades, a sleeve which ing and a finished outer end to form part of a guide bearing, other bearing members carried by the casing and co-operating with those of the ferrule, a gear attached to each ferrule, a tubular member, a gear which surrounds the member and is actuated thereby, a sleeve which is guided on the hub and has a straight line motion, means between the sleeve and hub to prevent relative rotation thereof, other means between the sleeve and member for transforming axial movements. of the sleeve into angular movement of the member, and means for moving the sleeve axially.

5.. In a propeller, the combination of a hub, a casing carried by the hub which is made in two principal parts, the plane of division being perpendicular to the axis, said parts having enlarged recesses, blades each of which has a ferrule with a flanged inner end'located in one of the recesses, means for securing each blade in its ferrule, anti-friction bearings located in the recesses and engaging the ferrules, a 'bev-' eled gear attached to each ferrule, a .tubular member which is concentric with the hub, a beveled gear carried by one end of the member which meshes with-those on the side of the sleeve, gearing between the mem- 6. In a propeller, the combinationof a hub, a casing carried thereby, blades which are anchored in the casing against centrifugal stresses and are capable of angular adjustment to change their pitch, a tubular member, gearing between the member and the blades, a sleeve located between the hub and member which has integral splines on its inner surfaces engaging slots in the hub and integral splines on its periphery engaging corresponding slots in the inner wall of the member to cause angular movement of the member, and means for moving the sleeve axially.

-7. In a propeller, the combination of a hub which has a central .bore to receive the driving shaft and a flange at one end, a pressed metal casing made in two principal parts with flanges along the plane of division to receive clamping'bolts, means for-securing the casin to the flange, blades carried by the casing and arranged to turn therein on their axes, a sleeve splined to the hub, a tubular member splined to the out- .5

9 her and the blades for turning them, a ring which is attached to the casing and surrounds the member and in which the memher is free to turn, and means for adjusting the sleeve axially.

8. In a propeller, the combination of a hub, a casing composed of two principal parts, said parts having sockets to receive the blades, each socket having walls extending perpendicular to its axis to form strengthening ribs and bearing receiving recesses, a ferrule for each blade which has an enlarged flange at its inner end that is located in one of the inner recesses, said flange having a greater diameter than that 1 of the body of the socket, thrust and guide bearings located in the recesses in each socket which engage the ferrule, means for anchoring each blade in its ferrule, gears carried by the ferrules for turning them in their bearings, gear means for'turnrng said gears, and means for actuating said gear means.

9. In a propeller the combinatlon of a hub, a casing mounted thereon and having I20 blade receiving sockets and bearing recelv ing recesses, said casing being div1ded 1nto two principal parts, the plane of division being perpendicular to the axis of the hub, means for uniting the parts of the cas ng, .126 blades located in the sockets, a-- one piece ferrule for each blade which is located in a socket and has an enlarged flange as its inner end situated in a recess in the casing and a finished surface at its outer end, means for between the hub and member and in telescopic relationthereto, splines located between the hub and sleeve, other splines located between the sleeve and vmember, and means for moving the sleeve to cause said splines to turn the blades in their axes to change their pitch..

a 11. In a propeller, the combination of' a hub adapted to be secured to the driving shaft, a casing secured to the hub, blades carried by the casing, a tubular member which surrounds the hub, gearin for transmitting motion from the mem r to the blades, a sleeve located between the hub and member, splines arrangbd internally and externally with respect to the sleeve and 00- operating with the hub and member for causing relatively angular movement of the V memberwith respect to the hub, and means for moving the sleeve.

In witness whereof, I have hereunto set my hand this 21 day of January, 1920.

O. F. PERSSON. 

